If I was sure they would fit a 66 225, I would take a valve cover and oil pan. I have a 44,000 original mile motor that was sitting with the pan on the ground for awhile -really crusty!!!
They are off a 225 /6 somewhere in the 70's the only part is the oil pan I do not know if it's car or truck they have 265 stamped on the oil pan.If that helps